The invention relates to an apparatus for comminuting organic substances, in particular for tearing apart fruits, including a stand, a tearing bed supported in the stand and having one surface as a travel path for the fruits, which path has tearing elements and next to them openings for the comminuted substances, the tearing elements protruding above the travel path by a height, and including means, supported in the stand, for delivering the organic substances to the tearing bed, and drive means for generating a relative motion between the tearing elements and the delivery means and the organic substances.
A drum-type cutting machine, particularly for cutting sugar beets into pieces, is known from U.S. Pat. No. 4,584,919 (Bittner). It has a number of retaining elements that are disposed at equal spacings over the circumference of the drum and extend substantially parallel to the axis of the drum. A knife chest in which at least one cutting knife whose cutting edge extends substantially circumferentially is secured is retained between each two retaining elements.
Various embodiments of drum mills of this type are also known for tearing apart fruits, such as the types sold under the name Central by Bucher-Guyer AG, Niederweningen, Switzerland. A drum mill of this kind includes a drum body, made in one piece, over whose circumference retaining elements for the tearing knives are disposed at small spacings. In the operationally ready state, the drum of such a mill forms a substantially closed hollow chamber, with an axial opening on one side through which the fruits to be torn apart are delivered by means of a transporting screw.
FIG. 2 in a detail shows the tearing apart of an apple in a known drum mill of this kind. Here the tearing bed takes the form of a drum 1, on whose inner surface 2 the travel path for the apples 3 along with the tearing knives 4 is located, shown in FIG. 2 in a section perpendicular to the drum axis. The drum 1 is stationary, while the apples 3 are fed through a screw, not shown, and are guided by vanes 5 of a rotor 6 at a speed v and a centrifugal force F over the surface 2 having the tearing knives 4.
One opening 7, as an outflow channel for the comminuted mash pieces 8 torn from the apples 3, is disposed between each two tearing knives 4. The outflow channels 7 extend axially at a spacing 9 parallel from the respective adjacent tearing knife 4. From FIG. 2 it can be seen that the apple 3 is thrust with high contact pressure F across the tearing knife 4. Given the known position of the outflow channels 7, theoretically a very long elongated piece 8 of flesh must have broken out of the apple 3 and entered the outflow channel 7, counter to the direction of motion v of the apple. In practice, this is highly unlikely. Experience tells that a large proportion of the pieces 8 of mash is thrust across the tearing knives 4 and thus reaches the subsequent outflow channel 7.
When the fruit is carried away in uncontrolled fashion in this way, the result is partial destruction of the mash structure because of the high pressing and friction forces that occur. Especially with soft fruit, this leads to a high proportion of fine particles in the mash, which very disadvantageously reduces the yield and output in an ensuing operation of juice extraction by pressing. Practical experience shows that even using tearing knives 4 with a very coarsely toothed tearing edge hardly decreases this proportion of fine particles.
The object of the invention is to overcome the above disadvantages of the known apparatuses for comminuting organic substances by means of a novel design.
According to the invention, this object is attained, in an apparatus of the type described at the outset, in that the openings in the tearing bed for the comminuted substances are disposed upstream of the tearing elements, in terms of the direction of relative motion, at a spacing which is less than the height of the tearing elements above the travel path. Versions in which the openings in the tearing bed directly adjoin the tearing elements are highly advantageous. Preferably, the openings are widened in the direction of passage of the comminuted substances. Further advantageous variants of the apparatus are defined by the claims.
A design of the apparatus according to the invention allows unhindered breaking out and expulsion of the torn-off (xe2x80x9cwrenched-offxe2x80x9d) mash particles 8 from the fruit 3 into the outflow channels 7. The mash particles 8 undergo no additional stresses. The design, because of a selectable height of the knifelike tearing elements above the travel path of the tearing bed, permits direct variation of the mash structure, and the comminuted organic substances have only very small proportions of fine particles. Because of the improved removal of the mash with less friction, the energy required for comminution with the apparatus is reduced.